Development of new radiopaque glass fiber posts.

The aim of this study was to analyze the radiopacity and filler content of three experimental glass fiber posts (EGFP) in comparison with other glass/carbon fibers and metal posts from the dental market. Three EGFP were obtained by pultrusion of glass fibers in a polymer matrix based on 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropoxy)-phenyl]propane (bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA) monomers. Using intraoral sensor disks 27 posts, as well as mesiodistal sections of human molar and aluminum step wedges were radiographed for evaluation of radiopacity. The percentage compositions of fillers by weight and volume were investigated by combustion analysis. Two EGFP showed radiopacity higher than enamel. The commercial endodontic posts showed radiopacity as follows: higher than enamel, between enamel and dentin, and lower than dentin. The results showed statistically significant differences (p b 0.05)when evaluatedwith one-way ANOVA statistical analysis. According to combustion analyses, the filler content of the tested posts ranges between 58.84wt.% and 86.02wt.%. The filler content of the tested EGFP ranged between 68.91 wt.% and 79.04 wt.%. EGFP could be an alternative to commercial glass fiber posts. Futureglass fiber posts are recommended to present higher radiopacity than dentin and perhaps ideally similar to or higher than that of enamel, for improved clinical detection. The posts with a lower radiopacity than dentin should be considered insufficiently radiopaque. The radiopacity of some glass fiber posts is not greatly influenced by the amount of filler.

The effect of age, gender, and insertion site on marginal bone loss around endosseous implants: results from a 3-year trial with premium implant system.

OBJECTIVES: The goal of this study was to evaluate bone changes around endosseous implants in partially edentulous patients. MATERIALS AND METHODS: A total of 632 two-stage implants were placed in 252 patients. The implants had straight emergence profile, ZirTi surface, 3.3 to 5 mm diameter, and 8.5 to 13 mm length. Bone levels were assessed on orthopantomography immediately after surgery and after 36 months and marginal bone loss (MBL) was calculated from their difference. RESULTS: Cumulative survival rate was 98.73%. Overall MBL was 0.8 mm ± 0.03 (mean ± SEM). Higher MBL was observed around implants in the maxilla than in the mandible (P < 0.007). A relation between implant diameter and MBL (P < 0.0001) was observed in male and, more limitedly, female patients. Older patients had higher MBL in the maxilla, but not in the mandible (P < 0.0001). MBL progressively increased with age in male patients, but reached a peak already in the 50-60 years age group in the female subset (P < 0.001). CONCLUSIONS: The overall MBL is consistent with the available literature. Site difference and patient age and gender appear to significantly affect MBL, representing important factors to be considered during implant placement.

The influence of endodontic broken stainless steel instruments on the urinary levels of iron.

Previous studies on the endodontic broken stainless steel instruments have mainly focused on retrieval of specimens. However, the systemic consequences of the retained separated instruments need an investigation. The current study aimed to evaluate the correlation between broken stainless steel instruments inside the root canal space and the urinary level of iron (Fe) in patients. Sixty near-aged and same-gender patients were selected. Thirty patients in the control group had no endodontic treatment in their history, while the other 30 patients in the endodontic group had broken stainless steel instrument. The urine samples were collected in iron-free containers. All specimens were refrigerated for 1 day and then subjected to Fe level measurement by electrothermal atomic absorption spectrometry. Data were analyzed by Kolmogorov-Smirnov and t tests at P < 0.05. The correlation coefficients of age and sex were also evaluated in relation with Fe levels in the urine. The level of Fe did not show any significant increase in the experimental group (P > 0.05). There was a positive correlation between age and Fe levels of endodontic and control groups. However, the joint effects of age and sex on Fe levels were different for the two groups. The presence of broken stainless steel instruments inside the root canal space did not elevate the level of Fe in the urine of patients. However, this value was positively correlated with the patient age.

Correlation between endodontic broken instrument and nickel level in urine.

This study aims to evaluate the correlation between the presences of separated endodontic instrument inside the dental canal and the nickel (Ni) level in the urine samples of subjected patients. Same-gendered and near-aged participants were selected and were instructed to collect their urine in sterile nickel-free plastic containers. The procedures were carried out in the office, and samples were stored in low-temperature cooler for 1 day and then they were transferred to the laboratory for electrothermal atomic absorption spectrometry. The level of Ni was measured and the correlation coefficient was calculated. Data were analyzed using t tests, Pearson's correlation coefficients, and linear regression analysis, at a level of significance P < 0.05. The statistical analysis has showed significant difference in Ni level between endodontic and control groups (P < 0.05). There was no correlation between Ni level in urine and the age or time period of broken instrument inside the canal; however, Ni level of urine and the age of participants in experimental group has demonstrated a positive correlation. The amount of Ni element can be increased in the urine of patients who have experienced broken endodontic instrument inside the dental canal. However, there is no positive correlation between the remaining pieces of instruments inside the canal and the elevation of nickel amount in urine during the tested time period. This issue suggested that the aging of remaining broken instrument inside the canal does not show any remarkable concern regarding the Ni elevation in the urine excreted by an individual.

Measurement of cortical bone thickness in adults by cone-beam computerized tomography for orthodontic miniscrews placement.

The purpose of this study was to investigate the cortical bone thickness of the inter-dental area of both jaws for orthodontic miniscrew placement. The cone-beam computerized tomography images of 32 non-orthodontic adults with normal occlusion were taken to measure the cortical bone thickness in both jaws. One-way analysis of variance (ANOVA) was used to analyze the differences in cortical bone thickness. Buccal cortical bone in the mandible was thicker than that in the maxilla. In the maxilla, cortical bone thickness was thicker in the buccal side than in the palatal side. Buccal cortical bone thickness in the mandible was thickest at the site distal to the first molar, and in the maxilla it was thickest at the site mesial to the first molar, while in the palatal side of maxilla it was thickest at the site mesial to the second premolar. The changing pattern of cortical bone thickness varies at different sites. In the buccal side of maxilla, the thinnest cortical bone thickness was found to be at 4 mm level from the alveolar crest, while the thickest was at 10 mm level (except for the site mesial to the first premolar). The buccal cortical bone thickness at the sites mesial or distal to the first molar in the mandible and palatal cortical bone thickness of maxilla tended to increase with increasing distance from the alveolar bone.

Influence of axial movement on fatigue of ProFile Ni-Ti rotary instruments: an in vitro evaluation.

The aim of this study was to evaluate the influence of the axial movement and the angle of curve (in degrees) on fatigue of nickel-titanium (Ni-Ti) ProFile rotary endodontic instruments. Ni-Ti ProFile rotary instruments (Maillefer SA, Ballaigues, Switzerland), 25 mm long in the range of ISO size 15 to 40 with two tapers (0.4 and 0.6) were evaluated. They are divided in two groups: the instruments with axial movement and those without axial movement. The system used to test the fatigue is maintained in mechanical conditions as close as possible to the clinical situation. The axial movement is in the order of 2 mm in corono-apical direction with a frequency of 1 Hz. The concave radii incorporating a notched V-form for guiding the instruments were: 5; 7,5 and 10 mm. The rotary system is mounted on an electric handpiece and rotated at 350 rpm speed as recommended by the manufacturers. The instruments are rotated until their separation, and the time, in seconds, is recorded. Statistical evaluation is undertaken using a two-way t-test to identify significant differences between variables in the study (p <0.05). We found significant statistical difference (p<0.05) between Ni-Ti engine drive ProFile instruments incorporating an axial movement and the instruments without axial movement with the same radius of curvature, size and taper.The incorporation of the axial movement increases significantly the life-span of the ProFile rotary instruments. This should reduce the risk of the instrument separation during the endodontic treatment.

Intraradicular splinting with endodontic instrument of horizontal root fracture--case report.

This case report describes the treatment of a horizontal mid-root-fractured incisor with an alternative fixation technique. As a result of clinical signs of pulpal necrosis, both the coronal and the apical root fragments were endodontically treated and obturated at single visit, and the fragments were stabilized internally through insertion of a stainless-steel endodontic file into the root canal. Four-year follow-up examination revealed satisfactory clinical and radiographic findings with hard tissue repair of the fracture line. This technique can be a quick remedy for patients with root-fractured tooth, especially for those who cannot make a second visit to the dental clinic.

Finite element stress analysis of cuneiform and cylindrical threaded implant geometries.

Statement of problem. Different implant geometries present different biomechanical behaviors and in this context, one arising question is how cuneiform implant geometry compares to clinical successful cylindrical threaded implant geometry. Purpose. The purpose of this work was to study stress distribution around cuneiform and cylindrical threaded implant geometries using three-dimensional finite element stress analysis taking the latter as a reference. Material and methods. A model was generated from a computerized tomography of a human edentulous mandible with implants placed in the left first premolar region. The model was supported by the mastication muscles and by temporomandibular joint. A vertical load of 100N was applied at the top of each implant in the direction of their long axes. The mandibular boundary conditions were modeled considering the actual muscle supporting system. Taking muscle forces intensities and directions, balance moment equations were employed to assess the system equilibrium. Cortical and medullary bones were assumed to be homogeneous, isotropic and linearly elastic. Results. The analysis provided results for maximum (S1) and minimum (S2) principal stress and Von Mises (SEQV) stress field. For both geometries, the results showed concentration on one side of the neck, smooth stress distribution along the body and no considerable concentration at the apical area. Conclusion. Results showed similar stress distribution pattern for cuneiform and cylindrical threaded geometries. The stresses profiles along the implants length reproduced their morphology. In both occurred stress concentration at one side of the neck and no body or apical stress concentration.

[Experimental substantiation of parameters and strength characteristics of new endodontic-endoosseous implant construction].

Postoperative tooth stump is not able to endure usual functional loads adequately that leads to enhanced resorption of bone tissues surrounding root and loss of the tooth. Based on math computer simulation of mode of deformation of biomechanical model "metal-ceramic construction--endodontic-endoosseous implant (EEI)--stump of operated tooth--bone tissue of the jaw" new domestic EEI parameters were elaborated which improved greatly biomechanical properties of tooth with operated roots. Strength characteristics of new EEI were studied. A set of instruments for EEI was developed.

[The well-established Dalbo-Rotex-retainer and the newly developed Ticap-system. Low-cost anchorage possibilities in the removable prosthesis]. / Der altbewährte Dalbo-Rotex-Wurzelanker und das neu entwickelte Ticap-System. Kostengünstige Verankerungsmöglichkeiten in der abnembaren Prothetik.

Conventional retainers for removable prostheses are frequently used in the daily practice. Financial limits, physical and mental restrictions especially among elderly or disabled patients, and/or limited prognosis of abutment teeth may require simple and less expensive alternatives. For these indications the well-established Dalbo-Rotex-retainer and the newly developed Ticap-system are available. Both systems are options for the anchorage of removable prostheses. Their clinical use is presented; furthermore their advantages and restrictions are discussed.

A six-year study of hydroxyapatite-coated root-form dental implants.

BACKGROUND: The effect of hydroxyapatite coating of dental implants is controversial. The long-term fate of hydroxyapatite-coated implants has been the subject of some criticism. PURPOSE: The aim of this retrospective study was to assess the clinical outcome of hydroxyapatite-coated cylindrical root-form endosseous Impladent dental implants (LASAK Ltd, Prague, Czech Republic) during a six-year course. METHODS: Three-hundred and ninety-one consecutively placed implants were used in 169 patients and followed for four to six years. Interval and cumulative success of implants and prostheses survival was tabulated. Marginal bone loss was measured RESULTS: Of the total number of implants, 98.5% achieved initial osseointegration. The cumulative success was 98.3% after one year, 97.0% after three years, 92.8% after five years and 90.4% after six years. The prostheses survival at the end of the study was 100% for fixed bridges totally supported by implants, 96.5% for fixed bridges with combined implant and tooth support, 94.2% for single crowns, 90.9% for mandibular overdentures and 81.3% for maxillary overdentures. Marginal bone loss averaged 2.4 +/- 0.8 mm at the end of five years. CONCLUSION: The success rate of the investigated hydroxyapatite-coated implants was comparable with the data presented in the literature and with the results of the similar implants without hydroxyapatite-coating. However, the marginal bone loss was of interest. Longer monitoring of the implants is necessary.

[Mechanical properties of nickel-titanium files following multiple heat sterilizations]. / Effetto delle procedure di sterilizzazione sulle proprietà meccaniche di strumenti endodontici in nickel-titanio.

AIM: The effect of cycles of sterilization procedures on nickel-titanium (NiTi) endodontic instruments is a serious concern for practitioners. There is no agreement in the literature whether these procedures could adversely affect the mechanical properties of endodontic files, and, consequently, increase the risk of intracanal failure. The purpose of this study was to evaluate the mechanichal resistance of Hero (MicroMega, Besancon, France) instruments, before and after sterilization procedures. METHODS: Thirty 02, 04, 06 tapered Hero size 30 new instruments were chosen and divided into 3 groups. Group A (control) were tested according to ANSI/ADA Spec.no 28 for torsional resistance, angle of torque and angle at breakage (45 inverted exclamation mark ). Group B files were first sterilized with chemiclave for 10 cycles of 20 minutes at 124 inverted exclamation mark C and then tested as described above. Group C files were first sterilized with glass beads for 10 cycles of 20 sec. at 250 inverted exclamation mark C and then tested as described above. Data were collected and statistically analyzed (t-paired test). Differences among the 3 groups were statistically not significant for both tests. RESULTS: All data were well within Spec.no 28 standard values. CONCLUSION: From the results of the present study, we may conclude that repeated sterilization procedures do not adversely affect the mechanichal resistance of Hero files.

Endodontic instruments for root canal therapy.

This article on endodontic instrumentation includes endodontic instruments and techniques of root-canal preparation of teeth in veterinary patients. Familiarity with instruments covered in this article and with advances in veterinary endodontics has become necessary for the veterinary dental practitioner who wishes to practice dentistry using current techniques. Veterinary endodontic techniques that help to retain the teeth longer are increasing in demand as an option to extracting damaged teeth. Endodontic treatment involves removal of the irreversibly damaged pulp, followed by cleaning and shaping of the root canal space using endodontic instruments and subsequent filling, or obturation, with a semisolid material and a sealer.

Periodontal healing after intentional auto-alloplastic reimplantation of injured immature upper front teeth.

BACKGROUND/AIMS: Conventional endodontic treatment results in high complication quota when performed in immature teeth. Intentional reimplantation with extraoral insertion of an endodontic implant (auto-alloplastic reimplantation) is an alternative. METHOD: In a retrospective study, the healing of 40 teeth reimplanted intentionally according to this method in patients aged 7 to 15 years was evaluated. Clinical tests (palpation, percussion sound, periotest values) and radiographical examinations were used to determine the type of periodontal healing (inflammatory resorption/periodontitis apicalis; replacement resorption/ankylosis; normal healing). RESULTS: Mean lifetime of the replanted teeth was 59.2+/-42.5 months, estimated survival time on the basis of the Kaplan-Meier analysis was 99.5 months. 17 teeth (42.5%) were classified as failures, mostly due to inflammatory resorption or periodontitis apicalis. Further investigations demonstrated that success rate and retention period of intentionally replanted teeth depend on the preoperative condition of the pulp. Teeth with preoperative infection suffered frequently from inflammatory resorption or periodontitis apicalis after being replanted (14 of 28 teeth). Estimated survival time according to Kaplan-Meier was 75.5 months. In contrast, inflammations or progressive resorptions were not observed in teeth without preoperative infection of the pulp. All these 12 teeth showed normal periodontal healing and regular tooth mobility. In the absence of any pathology in clinical or radiological findings after an average functional period of 72.3 months, the prognosis can be presumed excellent. Estimated survival time of 148.3 months according to Kaplan-Meier differs significantly from survival time of teeth infected preoperatively. CONCLUSIONS: From the results of this investigation, it may be concluded that an infection of the pulp - due to delay of treatment or attempts at endodontic therapy - should be avoided before intentional replantation of immature front teeth with pulp necrosis. Periodontal healing of the autologous root is not impaired by the insertion of posts made of Al2O3-ceramics or titanium. The inserted posts do not ankylose. Orthodontic movement of auto-alloplastically replanted teeth is possible.

Application of titanium-alloy endodontic implants in conjunction with periradicular surgery.

OBJECTIVE: To evaluate the outcome of placement of titanium-alloy endodontic implants in conjunction with periradicular surgery. STUDY DESIGN: Twenty-four teeth were treated with endodontic implants with corresponding periradicular surgery by using SuperEBA cement (Harry J Bosworth Co, Skokie, Ill) as a sealer. The results of the endodontic implant surgery were evaluated clinically and radiographically from 2 to 4 years after treatment. RESULTS: Twenty-two teeth were treated successfully, whereas 2 teeth were treated unsuccessfully, for a success rate of 92%. CONCLUSIONS: Titanium-alloy endodontic implants in conjunction with periradicular surgery may provide good short-term results. Sealing between the endodontic implant and the dentin is likely an important factor for success.